In the related art, a drive control device for a motor detects a current flowing through a MOS transistor forming an H switch that supplies an excitation current to an excitation coil by detecting a voltage generated in a resistor connected to the H switch, and controls ON/OFF of the MOS transistor forming the H switch according to a value of the detected current.
However, power efficiency decreases due to electric power consumed by the resistor, heat is generated due to electric power consumed by the resistor, and cost increases for providing a highly accurate resistor. Therefore, various attempts are performed to detect the excitation current without providing the resistor. A drive control device which can control the excitation current with high accuracy and a control method thereof are desired.